![background image](http://html1.mh-extra.com/html/dankoff-solar-products/suncentric-p/suncentric-p_instruction-manual_3413455025.webp)
6.3 Suction-Lift Applications
THIS DOES NOT APPLY TO TYPICAL SWIMMING POOL APPLICATIONS
This refers to applications where the pump must be placed HIGHER than the surface of the water
source, like drawing from a shallow well, ditch, river, or pond.
WARNING Limit of suction height: The vertical distance from the surface of the water source to
the pump intake must not be more that 8 feet (subtract 1 foot for every 1000 feet elevation above
sea level).
Pumps are better at pushing than sucking. In all cases, suction height should be kept to a minimum. If
the water is hot or contains a high amount of dissolved gasses, air entrapment may cause loss of prime
at less than 8 feet. High altitude location reduces the suction capacity as well.
Special attention must be paid to the suction piping, to minimize its resistance to flow. It should slope
upward to the pump without dips or high points, so air pockets do not form. The highest point in the
suction piping should be the pump inlet.
Follow the same rules as for a drain pipe
— except that the water will be drawn upward. Water must
flow as quickly and easily as possible.
Foot valve
A foot valve must be used at the water intake, to keep the pump primed. Foot valves are
available from any local pump supplier. To prevent air from being drawn into suction pipe due to a
suction whirlpool, the foot valve may need to be submerged as much as three feet (1 m) below the low
water level. This will NOT add to the suction load on the pump. The suction pipe must be tight and free of
air leaks or the pump will not operate properly.
Priming the pump
Before starting the pump for the first time, remove the lock ring that secures the
transparent strainer lid. (Turn the ring counterclockwise.) Fill the strainer tank with water until it is level
with the suction inlet. The entire suction pipe and pump body must be full of water. Replace the lid,
making sure the O-ring is not damaged. Screw down the lock ring hand-tight only.
Tolerance for running dry
If the pump loses its prime or the water source goes dry, or an intake pipe
breaks, the pump is in danger of running dry. If the pump is completely dry inside, the shaft seal is
deprived of cooling and lubrication provided by water. This causes the seal to overheat, and may cause
the surrounding pump material to melt.
SunCentric P
is designed to hold a reservoir of water to prevent
this occurrence by splashing water against the seal. It can usually run for a period of a few hours or
possibly a day without water intake, before the seal is at risk. However, if dry run is a possibility, the use
of a low-water shutoff system is highly recommended. See the next section.
Содержание SunCentric P
Страница 29: ...8 5 Exploded View of Pump...